High efficiency tunable beam steering device based on pancharatnam phase
AssigneesKent State University, Government of the United States as Represented by the Secretary of the Air Force
InventorsBrandon Vreeland, Philip Bos, Andre Van Rynbach
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Abstract
A tunable optical beam steering device includes: a first means for providing surface localized in-plane electric fields on a first substrate and also on a second substrate that together define a sandwich structure containing a liquid crystal material; a second means for providing electric fields between the two substrates that can be at an angle to the surface normal, or along the surface normal; and an alignment layer on a surface of each substrate that causes the liquid crystal director to align with a small angle relative to the surface normal and whose projection onto the plane of the substrates is different on the two substrates.
Claims20
A tunable optical beam steering device comprising:
- a first means for providing surface localized in-plane electric fields on a first substrate and also on a second substrate that together define a sandwich structure containing a liquid crystal material;
- a second means for providing electric fields between the two substrates that can be at an angle to the surface normal, or along the surface normal;
- and
- an alignment layer on a surface of each substrate that causes a liquid crystal director to align with a small angle relative to the surface normal and whose projection onto the plane of the substrates is different on the two substrates;
- wherein the device is configured to apply a voltage scheme comprising in sequence:
- a first voltage step for setting an azimuthal angle of a liquid crystal optical axis at all locations to create a linear spiral director configuration;
- and
- a second voltage step for causing the director to lie in the plane of the cell;
- and
- wherein the first voltage step is configured to generate fringe electric fields and diagonal electric fields.
A tunable liquid crystal device comprising in sequence:
- a first common conductive layer;
- a first insulating layer;
- a first array comprising a first plurality of parallel electrodes;
- a first alignment layer;
- a liquid crystal layer;
- a second alignment layer;
- a second array comprising a second plurality of parallel electrodes;
- a second insulating layer;
- and
- a second common conductive plane;
- wherein each electrode of the first plurality is located directly across from a different electrode from the second plurality;
- and
- wherein the device is configured to apply a voltage scheme comprising in sequence:
- a first voltage step for setting an azimuthal angle of a liquid crystal optical axis at all locations to create a linear spiral director configuration;
- and
- a second voltage step for causing the director to lie in the plane of the cell;
- and
- wherein the first voltage step is configured to generate fringe electric fields and diagonal electric fields.
A process for controlling a director field in a tunable liquid crystal device, the liquid crystal device comprising:
- a first common conductive plane;
- a first insulating layer;
- a first array comprising a first plurality of parallel electrodes;
- a first alignment layer;
- a liquid crystal layer;
- a second alignment layer;
- a second array comprising a second plurality parallel electrodes;
- a second insulating layer, wherein each electrode of the first plurality is located directly across from a different electrode from the second plurality;
- and
- a second common conductive plane;
- the process comprising in sequence:
- a first voltage step for setting an azimuthal angle of a liquid crystal optical axis at all locations to create a linear spiral director configuration;
- and
- a second voltage step for causing the director to lie in the plane of the cell;
- wherein the first voltage step is configured to generate fringe electric fields and diagonal electric fields.
Dependencies are inferred from the claim text.